The present invention relates to a filter system for the air intake of internal combustion engines.
An air filter is described in published German Patent Application No. DE 197 56 247, which serves especially for cleaning the air taken in by an internal combustion engine. The air filter is of a substantially oval or elliptic shape. This has the purpose of improving the drainage of any water that might enter the filter and of improving the air throughput capacity of the filter.
The disadvantage of this shape is that, when this filter element becomes heavily loaded with dust, the difference in pressure between the raw air side and the clean air side increases very greatly, and this leads very soon to the clogging of the filter. Therefore an additional outside jacket is applied to this filter element, which is intended to hold out coarser particles this outer jacket, however, also requires additional space, so that the space saving effect of the oval filter is not achieved or is achieved only to a very limited extent.
A product separator is disclosed in published German Patent Application No. DE 196 18 198, which serves to separate solid particles from a gas stream. For this purpose, a filter cartridge is provided, which is arranged in a housing. The housing furthermore comprises a baffle which is intended to direct a portion of the inflowing solid particles directly into a container without loading the filter. A disadvantage of this so-called xe2x80x9cpre-separatorxe2x80x9d is that only relatively large dirt particles are removed. A large part of the dust and floating substances reaches the filter cartridge and leads to a rapid build-up of a filter cake which increases the resistance to flow.
It is the object of the invention to provide a filter which avoids these disadvantages and to create a filter system which exhibits a high degree of separation and at the same time a long useful service life. It is precisely in the use of farm machinery, utility vehicles or other machines that a very high degree of separation is required. Nevertheless the filter system required should not be bulky.
These and other objects are achieved in accordance with the invention by providing a filter system for the air intake of an internal combustion engine, the filter system comprising a housing, a pre-separator, a main filter element disposed in the housing, and a cover closing the housing, wherein both the housing and the filter element have a substantially oval contour which is adapted to the contour of a covering for the internal combustion engine.
In accordance with another aspect of the invention, the objects are achieved by providing a filter system for an air intake of an internal combustion engine, the filter system comprising an oval housing, a cover disposed at one end of the oval housing for closing the housing, the housing having a clean air outlet connection disposed opposite from the cover and an unfiltered air inlet provided on the geodetically lower side of the housing, at least one cyclone separator arranged to receive air from the unfiltered air inlet, the cyclone separator comprising a guide element, a dust collecting chamber, and a clean air opening, an oval, pleated filter element disposed in the housing, a radial sealing gasket sealingly interposed exteriorly of the pleated filter element between the pleated filter element and the clean air outlet such that a clean air space inside the clean air outlet is sealingly separated from a raw air space outside the pleated filter element, the pleated filter element having an end plate disposed opposite from the clean air outlet, and a compression spring disposed between the end plate of the pleated filter element and the cover of the housing such that the compression spring urges the pleated filter element against the clean air outlet and retains the pleated filter element in the housing.
In accordance with a still further aspect of the invention, the objects are achieved by providing a filter element for installation in a housing of an air filter system of an internal combustion engine; the filter element comprising an oval supporting body, a pleated paper main filter supported by the supporting body; a filter fleece also supported by the supporting body, a first end plate sealingly connected to the main filter, the first end plate having a gasket receptacle thereon, the gasket receptacle comprising two radially outwardly extending branches, a profiled gasket member disposed between the radially outwardly extending branches such that when the filter is installed in a housing, the gasket member produces a radial seal between the filter element and the housing, and a second end plate sealingly connected to the main filter opposite from the first end plate, the second end plate being closed and having a contour which receives a compression spring.
An important advantage of the invention is that the combination of an oval filter element requiring little space and having a centrifugal separator makes possible an especially compact form.
In accordance with one embodiment of the invention, a secondary element is provided within the filter system and within the main filter element. When the main filter element is replaced the secondary filter element remains on the clean air connection, so that the entry of dust or dirt into the clean air area is prevented during replacement of the main filter element.
In another embodiment of the secondary element, a fleece material is used. This fleece material has the advantage of assuring good protection of the clean air area combined with a low resistance to flow.
In another advantageous embodiment, which relates to the mounting of the main filter element, the main filter element is provided with an externally placed radial seal on the end facing the clean air connection. A compression spring thrusting on the one hand against the main filter element and on the other hand against a housing cover provides reliable support for the main filter element in the housing.
These and other features of preferred embodiments of the invention, in addition to being set forth in the claims, are also disclosed in the specification and/or the drawings, and the individual features each may be implemented in embodiments of the invention either individually or in the form of subcombinations of two or more features and can be applied to other fields of use and may constitute advantageous, separately protectable constructions for which protection is also claimed.